The other udevd logs (apparently competing with the extraneous systemd-udevd) belong to the eudev package, which I would have thought you installed as replacement. If not, then you have to chase up which binary is involved and where it comes from. Something like this (as root) perhaps:

# find /bin /sbin /lib /usr -name '*udev*

[    1.648553] systemd-udevd[197]: starting version 3.2.14

I don't think you should run both udev and eudev!! (It looks like you do)

Get rid of systemd-udevd first. But if that doesn't fix it we should look further.

Note : Don't mind the kernel version, I also use stock devuan kernel and it's same.

Which permissions does it have/get and which permissions would you want?
Do you use eudev?

before I set (some programs won't launch)

After I chmod it to 666 (mind the number, everything works fine).

Yes I'm using eudev.

How to mark this as unsolved ?

Done!

Answer about seatd and elogind would start with asking which "service managment" you are using; (apparently not sysvinit?)

About apt using ipv4 there's web results like this, suggesting by example:

sudo apt-get -o Acquire::ForceIPv4=true install pkg
sudo apt-get -o Acquire::ForceIPv4=true update
sudo apt-get -o Acquire::ForceIPv4=true upgrade
sudo apt-get -o Acquire::ForceIPv4=true dist-upgrade
sudo apt-get -o Acquire::ForceIPv4=true install ksh

- /dev/dri/renderD128 always has wrong permission, I need to chmod it in order to be used.
- seatd and elogind won't start automatically, I need to start it manually so I can launch wayland compositor.
- apt somehow need to be told to use IPv4, if not it will stuck at connecting (maybe) forever.

I don't bother with the last two, but for the first, I need to guidance to make it right. Any advice ? Thanks